src/interpreter.c

@@ -11,6 +11,8 @@
 
 int currentInstruction = 0;
 
+bool isMainScopeGlobal = true;
+
 [[noreturn]] void runtimeError(GroundRuntimeError error, char* what, GroundInstruction* where, int whereLine) {
     printf("Ground runtime error:\n  ErrorType: ");
     switch (error) {
@@ -78,6 +80,22 @@ int currentInstruction = 0;
     exit(1);
 }
 
+[[noreturn]] void throwError(GroundError* error) {
+    printf("Uncaught Ground runtime error:\n  ErrorType: %s\n", error->type);
+    if (error->what != NULL) {
+        printf("  ErrorContext: %s\n", error->what);
+    }
+    if (error->where != NULL) {
+        printf("  ErrorInstruction: ");
+        printGroundInstruction(error->where);
+        printf("\n");
+    }
+    if (error->line > -1) {
+        printf("  ErrorLine: %zu\n", error->line + 1);
+    }
+    exit(1);
+}
+
 GroundLabel* findLabel(GroundLabel* head, const char *id) {
     GroundLabel *item;
     HASH_FIND_STR(head, id, item);
@@ -438,6 +456,8 @@ GroundValue interpretGroundProgram(GroundProgram* in, GroundScope* inScope) {
         scope.labels = &labels;
         scope.variables = &variables;
     }
+    scope.isMainScope = isMainScopeGlobal;
+    isMainScopeGlobal = false;
     // Preprocess all labels, structs and functions
     for (size_t i = 0; i < in->size; i++) {
         if (in->instructions[i].type == CREATELABEL) {
@@ -872,6 +892,10 @@ GroundValue interpretGroundInstruction(GroundInstruction inst, GroundScope* scop
                     addVariable(scope->variables, in->args.args[1].value.refName, createStringGroundValue("none"));
                     break;
                 }
+                case ERROR: {
+                    addVariable(scope->variables, in->args.args[1].value.refName, createStringGroundValue("error"));
+                    break;
+                }
             }
 
             break;
@@ -1737,6 +1761,12 @@ GroundValue interpretGroundInstruction(GroundInstruction inst, GroundScope* scop
                 
                 if (function->nativeFn) {
                     GroundValue returnValue = function->nativeFn(scope, argsList);
+                    if (returnValue.type == ERROR) {
+                        if (scope->isMainScope) {
+                            throwError(&returnValue.data.errorVal);
+                        }
+                        return returnValue;
+                    }
                     if (returnValue.type != function->returnType) {
                          runtimeError(RETURN_TYPE_MISMATCH, "Unexpected return value type from native function", in, currentInstruction);
                     }
@@ -1756,6 +1786,9 @@ GroundValue interpretGroundInstruction(GroundInstruction inst, GroundScope* scop
                 size_t currentCurrentInstruction = currentInstruction;
                 currentInstruction = function->startLine;
                 GroundValue returnValue = interpretGroundProgram(&function->program, &newScope);
+                if (returnValue.type == ERROR) {
+                    return returnValue;
+                }
                 if (returnValue.type != function->returnType) {
                     runtimeError(RETURN_TYPE_MISMATCH, "Unexpected return value type from function", in, currentInstruction);
                 }

src/interpreter.h

@@ -29,6 +29,7 @@ typedef struct GroundVariable {
 typedef struct GroundScope {
     GroundLabel** labels;
     GroundVariable** variables;
+    bool isMainScope;
 } GroundScope;
 
 typedef struct GroundDebugInstruction {

src/types.c

@@ -51,6 +51,13 @@ GroundValue createFunctionGroundValue(GroundFunction* in) {
     return gv;
 }
 
+GroundValue createErrorGroundValue(GroundError in) {
+    GroundValue gv;
+    gv.data.errorVal = in;
+    gv.type = ERROR;
+    return gv;
+}
+
 GroundValue createNoneGroundValue() {
     GroundValue gv;
     gv.type = NONE;
@@ -168,6 +175,18 @@ void freeGroundValue(GroundValue* gv) {
         freeGroundStruct(gstruct);
         free(gstruct);
     }
+    if (gv->type == ERROR) {
+        GroundError* error = &gv->data.errorVal;
+        if (error->type != NULL) {
+            free(error->type);
+        }
+        if (error->what != NULL) {
+            free(error->what);
+        }
+        if (error->where != NULL) {
+            freeGroundInstruction(error->where);
+        }
+    } 
 }
 
 GroundArg createValueGroundArg(GroundValue value) {
@@ -529,3 +548,35 @@ void freeGroundObject(GroundObject* object) {
     }
     object->fields = NULL;
 }
+
+GroundError createGroundError(char* what, char* type, GroundInstruction* where, size_t* line) {
+    GroundError ge;
+    if (what != NULL) {
+        ge.what = malloc(strlen(what) + 1);
+        strcpy(ge.what, what);
+    } else {
+        ge.what = NULL;
+    }
+
+    if (type != NULL) {
+        ge.type = malloc(strlen(type) + 1);
+        strcpy(ge.type, type);
+    } else {
+        ge.type = "GenericError";
+    }
+
+    if (where != NULL) {
+        ge.where = malloc(sizeof(GroundInstruction));
+        *ge.where = copyGroundInstruction(where);
+    } else {
+        ge.where = NULL;
+    }
+
+    if (line != NULL) {
+        ge.line = *line;
+    } else {
+        ge.line = -1;
+    }
+
+    return ge;
+}

src/types.h

@@ -13,7 +13,7 @@ typedef enum GroundInstType {
 } GroundInstType;
 
 typedef enum GroundValueType {
-    INT, DOUBLE, STRING, CHAR, BOOL, LIST, FUNCTION, STRUCTVAL, CUSTOM, NONE
+    INT, DOUBLE, STRING, CHAR, BOOL, LIST, FUNCTION, STRUCTVAL, CUSTOM, ERROR, NONE
 } GroundValueType;
 
 typedef enum GroundArgType {
@@ -29,6 +29,7 @@ struct GroundFunction;
 struct GroundScope;
 struct GroundStruct;
 struct GroundObject;
+struct GroundInstruction;
 
 struct List;
 
@@ -42,6 +43,16 @@ typedef struct List {
     struct GroundValue* values;
 } List;
 
+/*
+ * Stores data associated with an error thrown during Ground execution.
+ */
+typedef struct GroundError {
+    char* what;
+    char* type;
+    struct GroundInstruction* where;
+    size_t line;
+} GroundError;
+
 /*
  * Stores literal values created in a Ground program.
  * Associated functions:
@@ -57,6 +68,7 @@ typedef struct GroundValue {
         char charVal;
         bool boolVal;
         List listVal;
+        GroundError errorVal;
         struct GroundFunction* fnVal;
         struct GroundStruct* structVal;
         struct GroundObject* customVal;
@@ -187,6 +199,9 @@ GroundValue createListGroundValue(List in);
 // Creates a GroundValue conatining (in), with type FUNCTION.
 GroundValue createFunctionGroundValue(GroundFunction* in);
 
+// Creates a GroundValue containing (in), with type ERROR.
+GroundValue createErrorGroundValue(GroundError in);
+
 // Creates a Groundvalue with type NONE.
 GroundValue createNoneGroundValue();
 
@@ -257,4 +272,9 @@ GroundObjectField* findField(GroundObject head, const char *id);
 // Frees a GroundObject
 void freeGroundObject(GroundObject* object);
 
+// Creates a GroundError.
+GroundError createGroundError(char* what, char* type, GroundInstruction* where, size_t* line);
+
+
+
 #endif